1. Field of the Invention
The present invention relates to a method for producing a multilayer ceramic substrate. In particular, the present invention relates to a method for producing a multilayer ceramic substrate including a plurality of stacked ceramic layers.
2. Description of the Related Art
Multilayer ceramic substrates including a plurality of stacked ceramic layers can be efficiently produced by simultaneously firing a source substrate including a plurality of multilayer ceramic substrates and cutting the source substrate into individual multilayer ceramic substrates after firing.
For example, Japanese Unexamined Utility Model Registration Application Publication No. 4-38071 discloses that ceramic green sheets having dividing lines are transferred and laminated to form a laminate, dividing grooves are formed by, for example, irradiating the dividing lines with a CO2 laser after the laminate is subjected to heat treatment, and the laminate is separated into many substrates.
Japanese Unexamined Patent Application Publication No. 5-75262 discloses that dividing grooves are formed in advance in either or both of front and back surfaces of press-bonded ceramic green sheets, and the resulting substrate is bent to form cracks along the dividing grooves after heat treatment, thereby separating the substrate into many substrates.
In Japanese Unexamined Utility Model Registration Application Publication No. 4-38071, however, an expensive, large-scale CO2 laser irradiation apparatus is required. The laser irradiation requires a long time. During cutting, the substrates may be broken by thermal strain, and deformation and/or alteration due to the heat of the laser may occur in sections of the substrate.
In the method disclosed in Japanese Unexamined Patent Application Publication No. 5-75262, in the press-bonded sheets after the formation of the dividing grooves, failures, such as deformation and breakage, may occur due to the dividing grooves during handling of the press-bonded sheets. When the heat-treated substrate is bent, the substrate may be broken at undesirable locations other than the grooves, resulting in defective articles. Although the substrate is separated along the dividing grooves, edges may have irregular shapes, resulting in out-of-specification products.